In recent years, many different types of levels have been developed and constructed. In one type of level, it is typical for the vial to be disposed within a circular opening formed in the web of a member having an I-beam-type cross section, with cover members being disposed on each side of the web to protect the vial. A common problem which exists in assembling such levels is to dispose the vial within the opening of the web so that the vial is accurately positioned relative to the working surface of the level. In one prior art arrangement, a pair of diametrically-opposed notches are formed in the periphery of the opening in order to position the vial without further adjustment. However, this method of construction is somewhat costly, since the diametrically-opposed notches must be precision formed with very little tolerance in order to ensure that the vial is accurately positioned and does not require adjustment. In addition, the cover members must be precision formed, as they include means for engaging the vial in order to properly position it relative to the plane of the web.
In another type of prior art arrangement, the vial is retained within one of the cover members, and then the cover members are connected by screws or the like to the web of the I-beam frame. However, as the cover member supporting the vial is connected to the web by screws, there is very little, if any, room for adjusting the position of the vial relative to the working surface of the level.
Accordingly, it has long been desired to provide a simple and inexpensive arrangement for accurately positioning a vial relative to the working surface of a level which does not require precision and expensive forming of parts and allows the vial to be quickly and easily adjusted within the level.
Broadly, it is an object of the present invention to provide an improved level which overcomes one or more of the aforesaid problems. Specifically, it is within the contemplation of the present invention to provide an improved level which allows quick and easy assembly of the level and vial, and which further allows the vial to be accurately positioned and adjusted in an efficient and simple manner without requiring relatively expensive, precision-formed parts.